Friedman, Y. Z.
Y. Zak Friedman is a Principal Consultant with Petrocontrol. He has practiced APC for most of his career, specializing in using first-principles models for inferential process control and has developed inferential models to fit many hydrocarbon processes. Dr. Friedman’s experience spans more than 50 yr, working with Exxon Research and Engineering, KBC Advanced Technology and Petrocontrol. He holds a PhD degree from Purdue University.
HP Control: How difficult is it to control absorber columns?
The absorber-stripper configuration is common for gas plants. If we are to apply advanced process control (APC) systems on a gas plant, it better to address the control problem—maximizing recover..
HP Control: Distillation column dual-temperature control—Part 2
Part 1 of this editorial1 has considered a distillation dual temperature control structure and concluded that such strategy is problematic and not likely to work. If you accept that dual-temperature c..
HP Control: Distillation column dual-temperature control-Part 1
This editorial takes issue with a claim by Mr. Greg Shinskey that distillation dual-composition control cannot be done effectively by a multivariable predictive controller (MPC), but can be done effec..
HP Control: Temperature points on main fractionators
Main fractionators are distillation columns that handle wide boiling curve feeds, cutting it into several products. Almost every major refinery unit has such a column, all with similar design features..
HP Control: APC designs for minimum maintenance—Part 3
This is the third in a series of three editorials about designing advanced process control (APC) applications for an environment of little to no maintenance. Having lamented for years about APC applic..
HP Control: APC designs for minimum maintenance—Part 2
My last month's editorial proposed that since our advanced process control (APC) applications are by and large under-maintained, these applications should be designed in the simplest possible way. The..
HP Control: APC designs for minimum maintenance—Part 1
I, and others, have written much about the difficulties of maintaining advanced process control (APC) applications.1–5 It is a problem to be tackled on many levels. There are issues of manning, t..
HP Control: CDU overhead double-drum configuration
Fig. 1 shows one of many CDU overhead configurations, with naphtha cutpoint control accomplished by a column top temperature controller manipulating a top pumparound (TPA) circuit heat removal. This c..
HP Reliability: To b(ias) or not to b(ias)? This is the question
How often would you bias an inferential model? Given the propensity of instruments to go off calibration, "never" is not a valid answer. "Every day upon receiving lab information" is an equally bad an..
HP Control: Where do you take those inferential models from?
Charts shown in my editorials, illustrating the performance of select first-principles models, have attracted much e-mail feedback. While mostly positive, some question why the editorials do not provi..
- Perpetual Next appoints Bilfinger as lead consultant for its Methanol Moerdijk project 4/1
- ASRock Industrial and CSI Validate O-PAS™ Systems Management Architecture with the iEP-7020E and AiSMA 4/1
- Heavy equipment for KazMunayGas' Atyrau PE plant ships from Shanghai to Kazakhstan 4/1
- KT Tech awarded early engineering works contract for 60,000-tpy SAF plant in Indonesia 4/1
- OCI Global completes sale of OCI Ammonia Holding to AGROFERT 4/1
- Union workers ratify contract at ExxonMobil's Louisiana (U.S.) refining and chemical complex 4/1
